1. Field of the Invention
The present invention relates to an ink jet recording apparatus having the functions of facsimile, copying machine, printer and the like, or usable as an output apparatus for a composite equipment, a work station and the like having such functions.
Also the present invention relates particularly to an ink jet recording apparatus having, as recording means, a so-called ink jet recording head of a full-line type having a recording width corresponding to the maximum recording width of a recording medium, or having a plurality of such recording heads for black ink or for inks of respectively different colors.
2. Related Background Art
Non-impact recording methods have recently been attracting attention due to their advantage that the noise level during the recording operation is negligibly low. Among these methods, ink jet recording is particularly promising because of the possibility of high speed recording and the capability of recording on ordinary paper without particular fixing treatment.
The recording head employed in the ink jet recording apparatus is generally provided with a small liquid discharge port (orifice), a liquid path, an energy applying part formed in said liquid path, and energy generating means for generating energy for liquid droplet formation, to be applied to the liquid present in said energy applying part.
For such energy generating means there are already known electromechanical converting members, such as a piezoelectric element; means for irradiation with an electromagnetic wave, such as a laser beam, which is absorbed in the liquid and generates heat therein for generating and discharging a liquid droplet; and electrothermal converting elements such as a heat-generating resistors for heating the liquid thereby discharging a liquid droplet. Among these, a recording head for causing liquid droplet discharge by thermal energy has various advantages as disclosed in the U.S. Pat. Nos. 4,740,796 and 4,723,129.
In contrast to the so-called serial scanning recording method in which the printing is conducted by reciprocating motion of the recording head on a stopped recording sheet, U.S. Pat. No. 4,692,778 discloses a fixed recording head consisting of an array of plural recording heads and enabling full-line printing. Said patent discloses various apparatuses, many of which have already been reduced to practice.
However a full-line recording head obtained by combining plural recording heads is expensive, and a complex structure is required for the positioning of each head. Also the entire recording head becomes inevitably bulky if plural full-line recording heads are employed.
Numerous designs of full-line recording heads consisting of a long single head for satisfying the requirements of compactization of the apparatus, stable image formation and high speed recording have been made, but have been unable, in any design, to avoid the drawbacks related to the means for recovering the discharge function of the recording head.
The present inventors have therefore reached a novel structure capable of preventing the drawbacks mentioned above.